Injections of various substances into avian eggs have been employed to decrease post-hatch mortality rates, increase the potential growth rates or eventual size of the resulting bird, and even to influence the gender determination of the embryo. Similarly, injections of antigens into live eggs have been employed to incubate various substances used in vaccines which have human or animal medicinal or diagnostic applications. Examples of substances that have been used for, or proposed for, in ovo injection include vaccines, antibiotics and vitamins. In addition, removal of material from avian eggs has been employed for various purposes, such as testing and vaccine harvesting. Examples of in ovo treatment substances and methods of in ovo injection are described in U.S. Pat. No. 4,458,630 to Sharma et al., U.S. Pat. No. 5,028,421 to Fredericksen et al., and U.S. Pat. Nos. 6,032,612 and 6,286,455 to Williams, the contents of which are incorporated by reference herein in their entireties.
An egg injection apparatus conventionally is designed to operate in conjunction with commercial egg carrier devices or flats. The injection apparatus may comprise a plurality of injection needles which operate simultaneously or sequentially to inject a plurality of eggs, or a single injection needle used to inject a plurality of eggs. The injection apparatus may comprise an “injection head” which comprises the injection needle or needles, and wherein each injection needle is in fluid communication with a source containing a treatment substance to be injected. A single fluid source may supply all of the injection needles in an injection device, or multiple fluid sources may be utilized.
An exemplary in ovo injection apparatus 10 is illustrated in FIG. 1. The illustrated apparatus 10 includes an egg carrier (e.g., an egg flat) 15 that supports eggs 20 for transport, a frame 16, and a plurality of injection delivery devices, or heads, 25 with fluid delivery means such as needles positioned therein in accordance with known techniques. The illustrated flat 15 holds a plurality of eggs 20 in a substantially upright position and is configured to provide external access to predetermined areas of the eggs 20. Specifically, each egg 20 can be contacted from above the flat 15 and from beneath the flat 15. Each egg 20 is held by the illustrated flat 15 so that a respective end thereof is in proper alignment relative to a corresponding one of the injection heads 25.
In ovo injection of substances (as well as in ovo extraction of materials) typically occurs by piercing an egg shell to form an opening (e.g., via a punch), extending an injection needle through the hole and into the interior of the egg (and in some cases into the avian embryo contained therein), and injecting treatment substance(s) through the needle and/or removing material therefrom. For example, each injection head 25 of the apparatus of FIG. 1 includes a punch 26 and an injection needle 27 with the punch surrounding the needle 27 in coaxial relationship therewith as illustrated in FIGS. 2A–2B. The punch 26 is configured to pierce the shell of an egg 20 so as to form an opening therein and the needle 27 is configured to deliver a substance into the egg 20 (FIG. 2B) via the opening.
Egg flats utilized in conjunction with in ovo injection apparatus typically contain an array of pockets that are configured to support a respective plurality of eggs in a generally upright orientation. An exemplary egg flat 15 is illustrated in FIGS. 3A–3B. The illustrated egg flat 15 includes a plurality of rows of pockets 32. Each pocket 32 is configured to receive one end 20a of a respective egg 20 so as to support the respective egg 20 in a substantially vertical position. Each pocket 32 of the illustrated egg flat 15 contains a plurality of tabs 34 that are configured to support a respective egg as illustrated in FIG. 4.
Although effective in supporting eggs during transport, these support tabs 34 can damage eggs during in ovo processing. The force applied to an egg by an in ovo processing punch or needle can push an egg downwardly against the support tabs 34 with sufficient force to cause the egg to crack. In addition to reducing hatch rates, cracked eggs can lead to contamination of other eggs within an egg flat, as well as contamination of processing equipment.
In addition, support tabs in conventional egg flats are typically somewhat flexible and may deflect when an egg supported thereby is punched. In addition, conventional egg flats themselves may be somewhat flexible. As such, during punching of a plurality of eggs, an egg flat structure may warp and/or twist. This warping and/or twisting of an egg flat may add to the deflection of the support tabs such that when the force of punching is removed the egg flat and tabs can grip an egg, thereby making removal of the egg from the egg flat difficult. Accordingly, it would be desirable to be able to punch through the shell of an egg supported within an egg flat without causing the egg to crack and without causing the egg to become stuck within the egg flat.